Detailed Understanding Society India and Beyond Class 9 Solutions and Class 9 Social Science SST Chapter 3 Atmosphere and Climate Question Answer NCERT Solutions make it easier to complete textbook exercises.
Class 9 SST Chapter 3 Atmosphere and Climate Question Answer
Class 9 Atmosphere and Climate Question Answer
The Big Questions (Page No. 39)
Question 1.
What is the composition of the atmosphere? (Page No. 39)
Answer:
The atmosphere is a mixture of gases consisting mainly of 78% nitrogen, 21% oxygen, 0.93% argon, 0.04% carbon dioxide, along with small amounts of other gases, water vapour and dust particles, which together make the Earth suitable for life.
Question 2.
How do the different layers of the atmosphere affect the planet Earth? (Page No. 39)
Answer:
The different layers of the atmosphere affect the planet Earth by performing different functions that protect and support life.
- The troposphere is the layer where weather changes occur.
- The stratosphere contains the ozone layer that protects us from harmful ultraviolet rays.
- The mesosphere burns up most meteoroids.
- The thermosphere absorbs harmful solar radiation and supports radio communication.
- The exosphere is the outermost layer that gradually merges into space.
Question 3.
What is the mechanism of monsoon? (Page No. 39)
Answer:
The monsoon is a seasonal wind system caused by the unequal heating of land and the sea. During summer, the land heats up faster than the surrounding oceans, creating a low-pressure area over the land and a high-pressure area over the oceans. Moist winds from the Indian Ocean, the Arabian Sea, and the Bay of Bengal move towards the land and bring heavy rainfall. During winter, the situation reverses as land cools faster than the surrounding oceans, causing winds to blow from land towards the sea. After passing over the Bay of Bengal, these winds absorb moisture and bring rainfall to Tamil Nadu, Andhra Pradesh, and parts of Karnataka. This seasonal reversal of winds is known as the monsoon mechanism.
Question 4.
How can we reduce our carbon footprint? (Page No. 39)
Answer:
We can reduce our carbon footprint by using public transport or bicycles, saving electricity and water, planting more trees, reducing waste, recycling materials, using renewable sources of energy, and adopting a sustainable lifestyle.
Class 9 Atmosphere and Climate Question Answer
InText Questions
Question 1.
Can you imagine what would happen if there were no atmosphere? Discuss your thoughts with your friends and teachers. (Page No. 39)
Answer:
If there were no atmosphere, there would be no air to breathe, no weather, and no rainfall. Harmful rays from the Sun would reach the Earth directly; temperatures would become extremely hot during the day and very cold at night, and life on Earth would not be possible.
Question 2.
You might have noticed that sometimes the wind is so strong that it is difficult to walk against it. Can you think of some other times when strong winds have caused problems for you? (Page No. 45)
Answer:
Strong winds can cause many problems, such as uprooting trees, damaging houses and electric poles, disrupting transport and power supply, creating dust storms and making it difficult to ride bicycles or motorcycles.
Question 3.
Find out other categories of wind based on speed and their common effects and share your findings in class. (Page No. 46)
Answer:
Winds are classified into different categories based on their speed, and their effects are
| Category of Wind | Common Effects |
| Light breeze | Leaves move gently, and the weather feels pleasant. |
| Moderate breeze | Small branches sway, and flags flutter. |
| Strong wind | Makes walking difficult and may break small branches. |
| Gale | Can damage trees, signboards, and weak structures. |
| Storm | Causes heavy damage to houses, trees, and power lines. |
| Cyclone/Hurricane | Produces very strong winds with heavy rain, leading to widespread destruction. |
Question 4.
Hindustani Classical music associates certain ragas with specific seasons. Find out which ragas are connected to each season with the help of your elders and teachers. (Page No. 48)
Answer:
Some Hindustani Classical ragas are associated with different seasons are
- Spring (Vasant): Raga Basant, Raga Bahar
- Summer: Raga Deepak (traditional association)
- Monsoon (Rainy Season): Raga Megh, Megh Malhar, Miyan ki Malhar
- Autumn: Raga Jaijaivanti
- Winter: Raga Hemant, Raga Pahadi
Question 5.
Describe in your own words how monsoon affects the lives of the people around you. (Page No. 52)
Answer:
The monsoon affects the lives of the people by providing water for drinking, farming, and daily use. It helps farmers grow crops and fills rivers, lakes, and reservoirs. However, heavy rainfall can also cause floods, waterlogging, traffic problems, and damage to crops, houses, and roads. Thus, the monsoon has both positive and negative effects on people’s lives.
Atmosphere and Climate Class 9 Questions and Answers
Questions and Activities (Page No. 57-59)
Question 1.
What is atmosphere? Explain its composition with the help of a pie diagram.
Answer:
The atmosphere is the blanket of gases that surrounds the Earth. It protects life by providing air to breathe, regulating temperature, and shielding the Earth from harmful solar radiation.
Question 2.
Draw a labelled diagram of the structure of the atmosphere.
Answer:
Question 3.
What are the four main seasons of India?
Answer:
The four main seasons of India are
- Summer Season (March – May)
- South-West Monsoon (Rainy Season) (June – September)
- Retreating Monsoon (October – November)
- Winter Season (December – February)
Question 4.
Why do you not feel the pressure of the atmosphere?
Answer:
We do not feel atmospheric pressure because the pressure of the air is balanced by the pressure inside our body. As atmospheric pressure acts equally in all directions, we do not notice it.
Question 5.
In which layer of the atmosphere do aeroplanes fly and why?
Answer:
Aeroplanes usually fly in the lower stratosphere because this layer has stable air and is free from most weather disturbances such as clouds, storms, and turbulence. This allows aircraft to fly smoothly, safely, and more efficiently, with lower fuel consumption.
Question 6.
Distinguish between the following:
(a) The troposphere and stratosphere
(b) The South-West monsoon and North-East monsoon
Answer:
(a) The differences between the troposphere and stratosphere are
| Troposphere | Stratosphere |
| It is the lowest layer of the atmosphere. | It is the second layer above the troposphere. |
| It extends from the Earth’s surface up to about 8 km – 18 km. | It extends from about 18 km to 50 km. |
| It contains about 75% of the atmospheric gases and almost all water vapour. | It contains very little water vapour. |
| Clouds, rain, storms and all weather phenomena occur in this layer. | It is almost free from clouds and weather disturbances. |
| Temperature decreases with an increase in height. | Temperature increases with increase in height due to the ozone layer. |
(b) The differences between the South-West Monsoon and North-East Monsoon are
| South-West Monsoon | North-East Monsoon |
| Blows from sea to land. | Blows from land to sea. |
| Occurs from June to September. | Occurs from October to November. |
| Brings most of India’s annual rainfall. | Brings rainfall mainly to Tamil Nadu and the South-Eastern coast. |
| Winds are moisture-laden. | Winds are generally dry, but pick up moisture over the Bay of Bengal before reaching Tamil Nadu. |
| Marks the onset of the rainy season. | Marks the retreating (withdrawal) monsoon season. |
Question 7.
Do it yourself: The table below shows the average monthly temperatures and rainfall amounts for 10 representative stations. Study these figures on your own and convert them into temperature and rainfall graphs. The visual representations will help you grasp their similarities and differences at a glance. One such graph is already prepared for you. See if you can arrive at some broad generalisations about our diverse climatic conditions.
Question 7.1.
Now look at the table above again. Re-arrange the 10 stations according to their distance from the equator.
Answer:
The 10 stations according to their distance from the equator are
| Order | Station | Latitude |
| 1 | Thiruvananthapuram | 8°29′ N |
| 2 | Bengaluru | 12°58′ N |
| 3 | Chennai | 13°4′ N |
| 4 | Mumbai | 19° N |
| 5 | Nagpur | 21°9′ N |
| 6 | Kolkata | 22°34′ N |
| 7 | Shillong | 24°34′ N |
| 8 | Jodhpur | 26°18′ N |
| 9 | Delhi | 29° N |
| 10 | Leh | 34° N |
Question 7.2.
Find out
(a) Two stations with the most extreme climate.
(b) Two stations influenced by the retreating monsoon.
(c) The two hottest stations in the months of (i) February (ii) June
Answer:
(a) The two stations with the most extreme climate are Leh and Delhi.
(b) The two stations influenced by the retreating monsoon are Chennai and Thiruvananthapuram.
(c) (i) In February, Thiruvananthapuram (26.7°C) and Chennai (25.7°C) are the two hottest stations.
(ii) In June, Delhi (33.3°C) and Jodhpur (33.3°C) are the two hottest stations.
Question 7.3.
Now find out
(a) Why does Shillong experience more rainfall than Kolkata?
(b) Why does Delhi receive more rainfall than Jodhpur?
Answer:
(a) Shillong receives more rainfall than Kolkata because the moisture-laden South-West monsoon winds are forced to rise over the Khasi Hills, causing heavy orographic rainfall.
(b) Delhi receives more rainfall than Jodhpur because Delhi is closer to the path of the Bay of Bengal branch of the South-West monsoon, which brings more moisture and rainfall. Jodhpur lies in the arid region of Western Rajasthan, where the Aravalli Hills run parallel to the monsoon winds and do not force them to rise, resulting in very little rainfall.
Question 7.4.
Now think why
(a) Thiruvananthapuram has an equable climate?
(b) Chennai has more rainfall only after the fury of the monsoon is over in most parts of the country?
(c) Leh has moderate precipitation almost throughout the year?
Answer:
(a) Thiruvananthapuram has an equable climate because it is located near the sea, and the sea moderates temperatures throughout the year.
(b) Chennai receives most of its rainfall during the retreating (North-East) monsoon in October and November, when the winds pick up moisture from the Bay of Bengal before reaching the Coromandel Coast.
(c) Leh receives moderate precipitation throughout the year because it lies in the rain-shadow region of the Himalayas, where the mountains block the moisture-laden monsoon winds, resulting in low rainfall.
Question 7.5.
Despite these differences across regions, can you observe any substantial evidence to conclude that the monsoons provide a very strong framework, lending overall climatic unity to the whole country?
Answer:
Despite regional differences in temperature and rainfall, the monsoon provides climatic unity to India. The South-West Monsoon brings rainfall to most parts of the country, supporting agriculture, filling rivers and reservoirs, and influencing the economy and daily life. Thus, the seasonal pattern of the monsoon gives India a common climatic character.
Question 8.
Collect pictures of houses and clothing of people from different regions of India. Examine whether they reflect any relationship with the climatic conditions or the relief of those regions.
Answer:
Yes, the houses and clothing of people from different regions of India reflect the climatic conditions and relief of those regions.
Houses and Clothing in Different Climatic Regions of India
| Region | Houses | Clothing | Reason |
| Himalayan Region | Houses with sloping roofs made of wood and stone | Woollen clothes | Cold climate and heavy snowfall |
| Rajasthan | Thick-walled houses with small windows | Light cotton clothes and turbans | Hot and dry desert climate |
| Coastal Regions (Kerala, Tamil Nadu) | Well-ventilated houses with sloping roofs | Light cotton clothes | Hot, humid climate and heavy rainfall |
| Assam | Houses built on stilts (raised platforms) | Light cotton clothes | Heavy rainfall and frequent floods |